She's hired 30 PhDs so far this year, with plans to hire another 20, Mayer said.

The research group is led by Chief Scientist Ron Brachman, who joined Yahoo in 2005. He's a former director for DARPA, the government agency that created the Internet and, he says, his work on artificial intelligence was the foundation for the Apple iPhone's Siri.

The group, known as Yahoo! Labs, was set up in 2005 with a mission "nothing short of inventing the future of the Internet," its web site proclaims.

Under Mayer's predecessor, Scott Thompson, funding for the group was cut and the group's leader, Prabhakar Raghavan, left in 2012 to become vice president of engineering at Google.

“The lab is still here -- it’s been reduced in size,” Mayer told MacMillan and Stone. She wants to reverse that so she's investing “heavily to build it back up,” she said.

While the group's projects aren't as spectacular as some of Google's (Google is working on things like self-driving cars, Google Glass, WiFi balloons in outer space), Yahoo! Labs is working on some cool things, too.